The present invention relates to spring tines for agricultural implements for soil cultivation, such as harrows, cultivators or the like, of the type which is provided with a curved spring blade whose upper end is designed as the fastening location for releasable fastening to the implement and whose lower end is releasably or nonreleasably connected with a carrier for the attachment of a working member, such as harrow tips, plowshares or the like.
An agriculturel implement for soil cultivation equipped with spring tines is dragged over the ground by means of a tractor. The working members of the spring tines thereby enter into the soil and loosen it. If a working member encounters a solid obstacle in the ground, the spring blade of the spring tine causes the tine to be elastically deformed. Thus, the working member is able to move around the obstacle.
German Auslegeschrift [Published Patent Application] No. 1,757,146 discloses a spring tine of the above-mentioned type. The spring blade of this spring tine has a cross section which is constant over its length and which is composed of two parallel long sides and two oppositely disposed short sides which form an approximate rectangle. The drawback of this known spring tine is that its spring blade of constant cross section is poorly utilized with respect to tension. When the spring tine is deflected, different stresses develop along the spring blade since different bending moments appear along its length. The point of greatest stress is at the cross section farthest removed from the point where the force attacks since the bending moment is known to be defined by force times lever arm. Thus, this uppermost cross section of a spring blade having a constant cross section is the point of maximum tension and thus the point at which the spring blade is in the greatest danger of breaking. To avoid the danger of breaking, in the prior art spring tines, there now exists the possibility of reinforcing the spring blade by means of a second spring blade or of enlarging the unvarying thickness of the spring blade as a whole, which, however, results in poorer material utilization of the spring steel.